Production of cefdinir is not simple and cefdinir is not always obtained in sufficient purity. For example, it is known that the preparation of cefdinir of formula
may be carried out whereby the acyl side chain on the amino group in position 7 of the cephalosporin ring structure may be introduced in the form of a (reactive) acid derivative of the 7-side chain, in which the oxime group is protected by an acetyl protecting group, after which the acetyl protecting group is cleaved in order to obtain cefdinir.
Published international application WO 98/45299 discloses a method for purification of cefdinir by formation of a crystalline dicyclohexylamine salt.